<!DOCTYPE HTML>
<html lang="en" class="sidebar-visible no-js">

<head>
    <!-- Book generated using mdBook -->
    <meta charset="UTF-8">
    <title>简单链表 &gt;&lt; Simple Linked List - exercisms.io 快速练习</title>
    <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
    <meta name="description" content="exercisms 的练习，网页版.">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta name="theme-color" content="#ffffff" />

    <link rel="shortcut icon" href="../favicon.png">
    <link rel="stylesheet" href="../css/variables.css">
    <link rel="stylesheet" href="../css/general.css">
    <link rel="stylesheet" href="../css/chrome.css">
    <link rel="stylesheet" href="../css/print.css" media="print">

    <!-- Fonts -->
    <link rel="stylesheet" href="../FontAwesome/css/font-awesome.css">
    <link href="https://fonts.googleapis.com/css?family=Open+Sans:300italic,400italic,600italic,700italic,800italic,400,300,600,700,800"
        rel="stylesheet" type="text/css">
    <link href="https://fonts.googleapis.com/css?family=Source+Code+Pro:500" rel="stylesheet" type="text/css">

    <!-- Highlight.js Stylesheets -->
    <link rel="stylesheet" href="../highlight.css">
    <link rel="stylesheet" href="../tomorrow-night.css">
    <link rel="stylesheet" href="../ayu-highlight.css">

    <!-- Custom theme stylesheets -->
    
    <link rel="stylesheet" href="../theme/custom.css">
    

    
</head>

<body class="light">
    <!-- Provide site root to javascript -->
    <script type="text/javascript">var path_to_root = "../";</script>

    <!-- Work around some values being stored in localStorage wrapped in quotes -->
    <script type="text/javascript">
        try {
            var theme = localStorage.getItem('mdbook-theme');
            var sidebar = localStorage.getItem('mdbook-sidebar');

            if (theme.startsWith('"') && theme.endsWith('"')) {
                localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
            }

            if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
                localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
            }
        } catch (e) { }
    </script>

    <!-- Set the theme before any content is loaded, prevents flash -->
    <script type="text/javascript">
        var theme;
        try { theme = localStorage.getItem('mdbook-theme'); } catch (e) { }
        if (theme === null || theme === undefined) { theme = 'light'; }
        document.body.className = theme;
        document.querySelector('html').className = theme + ' js';
    </script>

    <!-- Hide / unhide sidebar before it is displayed -->
    <script type="text/javascript">
        var html = document.querySelector('html');
        var sidebar = 'hidden';
        if (document.body.clientWidth >= 1080) {
            try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch (e) { }
            sidebar = sidebar || 'visible';
        }
        html.classList.remove('sidebar-visible');
        html.classList.add("sidebar-" + sidebar);
    </script>

    <nav id="sidebar" class="sidebar" aria-label="Table of contents">
        <ol class="chapter"><li><a href="../index.html"><strong aria-hidden="true">1.</strong> 超过 88 道练习，任点</a></li><li><a href="../low.html"><strong aria-hidden="true">2.</strong> 易</a></li><li><ol class="section"><li><a href="../hello-world/README.zh.html"><strong aria-hidden="true">2.1.</strong> hello world</a></li><li><a href="../gigasecond/README.zh.html"><strong aria-hidden="true">2.2.</strong> 千兆秒 &gt;&lt; Gigasecond)</a></li><li><a href="../leap/README.zh.html"><strong aria-hidden="true">2.3.</strong> 闰年 &gt;&lt; Leap</a></li><li><a href="../raindrops/README.zh.html"><strong aria-hidden="true">2.4.</strong> 雨滴声 &gt;&lt; Raindrops</a></li><li><a href="../reverse-string/README.zh.html"><strong aria-hidden="true">2.5.</strong> 反转字符串 &gt;&lt; Reverse String</a></li><li><a href="../nth-prime/README.zh.html"><strong aria-hidden="true">2.6.</strong> 第 n 个素数 &gt;&lt; Nth Prime</a></li><li><a href="../bob/README.zh.html"><strong aria-hidden="true">2.7.</strong> 迟钝孩子 &gt;&lt; Bob</a></li><li><a href="../beer-song/README.zh.html"><strong aria-hidden="true">2.8.</strong> 啤酒之歌 &gt;&lt; Beer Song</a></li><li><a href="../proverb/README.zh.html"><strong aria-hidden="true">2.9.</strong> 谚语串烧 &gt;&lt; Proverb</a></li><li><a href="../difference-of-squares/README.zh.html"><strong aria-hidden="true">2.10.</strong> 平方差 &gt;&lt; Difference Of Squares</a></li><li><a href="../sum-of-multiples/README.zh.html"><strong aria-hidden="true">2.11.</strong> 倍数之和 &gt;&lt; Sum Of Multiples</a></li><li><a href="../grains/README.zh.html"><strong aria-hidden="true">2.12.</strong> 谷物 &gt;&lt; Grains</a></li><li><a href="../pythagorean-triplet/README.zh.html"><strong aria-hidden="true">2.13.</strong> 勾股数 &gt;&lt; Pythagorean Triplet</a></li><li><a href="../prime-factors/README.zh.html"><strong aria-hidden="true">2.14.</strong> 素数因子 &gt;&lt; Prime Factors</a></li><li><a href="../series/README.zh.html"><strong aria-hidden="true">2.15.</strong> 子串 &gt;&lt; Series</a></li><li><a href="../armstrong-numbers/README.zh.html"><strong aria-hidden="true">2.16.</strong> 水仙花数 &gt;&lt; Armstrong Numbers</a></li><li><a href="../collatz-conjecture/README.zh.html"><strong aria-hidden="true">2.17.</strong> 3n+1 猜想 &gt;&lt; Collatz Conjecture</a></li><li><a href="../diffie-hellman/README.zh.html"><strong aria-hidden="true">2.18.</strong> 迪菲-赫尔曼密钥交换 &gt;&lt; Diffie Hellman</a></li></ol></li><li><a href="../medium.html"><strong aria-hidden="true">3.</strong> 中等</a></li><li><ol class="section"><li><a href="../saddle-points/README.zh.html"><strong aria-hidden="true">3.1.</strong> 鞍点 &gt;&lt; Saddle Points</a></li><li><a href="../isogram/README.zh.html"><strong aria-hidden="true">3.2.</strong> 等值线 &gt;&lt; Isogram</a></li><li><a href="../say/README.zh.html"><strong aria-hidden="true">3.3.</strong> 英文说数字 &gt;&lt; Say</a></li><li><a href="../run-length-encoding/README.zh.html"><strong aria-hidden="true">3.4.</strong> 游程编码 &gt;&lt; Run Length Encoding</a></li><li><a href="../isbn-verifier/README.zh.html"><strong aria-hidden="true">3.5.</strong> 图书编号 &gt;&lt; ISBN Verifier</a></li><li><a href="../perfect-numbers/README.zh.html"><strong aria-hidden="true">3.6.</strong> 数字也能分类 &gt;&lt; Perfect Numbers</a></li><li><a href="../clock/README.zh.html"><strong aria-hidden="true">3.7.</strong> 时钟 &gt;&lt; Clock</a></li><li><a href="../dot-dsl/README.zh.html"><strong aria-hidden="true">3.8.</strong> DOT DSL</a></li><li><a href="../hamming/README.zh.html"><strong aria-hidden="true">3.9.</strong> 汉明距离 &gt;&lt; Hamming</a></li><li><a href="../simple-linked-list/README.zh.html" class="active"><strong aria-hidden="true">3.10.</strong> 简单链表 &gt;&lt; Simple Linked List</a></li><li><a href="../pascals-triangle/README.zh.html"><strong aria-hidden="true">3.11.</strong> 杨辉三角形 &gt;&lt; Pascal's Triangle</a></li><li><a href="../scrabble-score/README.zh.html"><strong aria-hidden="true">3.12.</strong> 字母的分数游戏 &gt;&lt; Scrabble Score</a></li><li><a href="../pangram/README.zh.html"><strong aria-hidden="true">3.13.</strong> 全字母句 &gt;&lt; Pangram</a></li><li><a href="../paasio/README.zh.html"><strong aria-hidden="true">3.14.</strong> PaaS-IO-报告 &gt;&lt; Paasio</a></li><li><a href="../nucleotide-count/README.zh.html"><strong aria-hidden="true">3.15.</strong> 核苷酸计数 &gt;&lt; Nucleotide Count</a></li><li><a href="../luhn/README.zh.html"><strong aria-hidden="true">3.16.</strong> 模 10 算法 &gt;&lt; Luhn</a></li><li><a href="../largest-series-product/README.zh.html"><strong aria-hidden="true">3.17.</strong> 最大数字子串乘积 &gt;&lt; Largest Series Product</a></li><li><a href="../word-count/README.zh.html"><strong aria-hidden="true">3.18.</strong> 单词计数 &gt;&lt; Word Count</a></li><li><a href="../atbash-cipher/README.zh.html"><strong aria-hidden="true">3.19.</strong> Atbash 加密 &gt;&lt; Atbash Cipher</a></li><li><a href="../crypto-square/README.zh.html"><strong aria-hidden="true">3.20.</strong> 密码矩形 &gt;&lt; Crypto Square</a></li><li><a href="../rotational-cipher/README.zh.html"><strong aria-hidden="true">3.21.</strong> 旋转密码 &gt;&lt; Rotational Cipher</a></li><li><a href="../simple-cipher/README.zh.html"><strong aria-hidden="true">3.22.</strong> 简单加密 &gt;&lt; Simple Cipher</a></li><li><a href="../rail-fence-cipher/README.zh.html"><strong aria-hidden="true">3.23.</strong> 栅栏密码 &gt;&lt; Rail Fence Cipher</a></li><li><a href="../etl/README.zh.html"><strong aria-hidden="true">3.24.</strong> ETL</a></li><li><a href="../accumulate/README.zh.html"><strong aria-hidden="true">3.25.</strong> 集合操作 &gt;&lt; Accumulate</a></li><li><a href="../acronym/README.zh.html"><strong aria-hidden="true">3.26.</strong> 术语 &gt;&lt; Acronym</a></li><li><a href="../sieve/README.zh.html"><strong aria-hidden="true">3.27.</strong> 素数筛 &gt;&lt; Sieve</a></li><li><a href="../rna-transcription/README.zh.html"><strong aria-hidden="true">3.28.</strong> RNA 转录 &gt;&lt; RNA Transcription</a></li><li><a href="../triangle/README.zh.html"><strong aria-hidden="true">3.29.</strong> 三角形</a></li><li><a href="../roman-numerals/README.zh.html"><strong aria-hidden="true">3.30.</strong> 罗马数字 &gt;&lt; Roman Numerals</a></li><li><a href="../all-your-base/README.zh.html"><strong aria-hidden="true">3.31.</strong> 你所的基本</a></li><li><a href="../grade-school/README.zh.html"><strong aria-hidden="true">3.32.</strong> 学册</a></li><li><a href="../binary-search/README.zh.html"><strong aria-hidden="true">3.33.</strong> 二分查找</a></li><li><a href="../robot-simulator/README.zh.html"><strong aria-hidden="true">3.34.</strong> 机器人模拟器</a></li><li><a href="../bracket-push/README.zh.html"><strong aria-hidden="true">3.35.</strong> 括号配套</a></li><li><a href="../luhn-from/README.zh.html"><strong aria-hidden="true">3.36.</strong> Luhn From</a></li><li><a href="../queen-attack/README.zh.html"><strong aria-hidden="true">3.37.</strong> 皇后 攻击</a></li><li><a href="../bowling/README.zh.html"><strong aria-hidden="true">3.38.</strong> 保龄球</a></li><li><a href="../sublist/README.zh.html"><strong aria-hidden="true">3.39.</strong> 子列表</a></li><li><a href="../space-age/README.zh.html"><strong aria-hidden="true">3.40.</strong> 地球年</a></li><li><a href="../luhn-trait/README.zh.html"><strong aria-hidden="true">3.41.</strong> Luhn Trait</a></li><li><a href="../macros/README.zh.html"><strong aria-hidden="true">3.42.</strong> 宏</a></li><li><a href="../allergies/README.zh.html"><strong aria-hidden="true">3.43.</strong> 过敏</a></li><li><a href="../variable-length-quantity/README.zh.html"><strong aria-hidden="true">3.44.</strong> 可变长度数量</a></li><li><a href="../phone-number/README.zh.html"><strong aria-hidden="true">3.45.</strong> 电话号码</a></li><li><a href="../wordy/README.zh.html"><strong aria-hidden="true">3.46.</strong> 罗唆</a></li><li><a href="../tournament/README.zh.html"><strong aria-hidden="true">3.47.</strong> 比赛</a></li><li><a href="../custom-set/README.zh.html"><strong aria-hidden="true">3.48.</strong> 自定义 set</a></li><li><a href="../alphametics/README.zh.html"><strong aria-hidden="true">3.49.</strong> 字母谜题</a></li><li><a href="../two-bucket/README.zh.html"><strong aria-hidden="true">3.50.</strong> 两个桶</a></li><li><a href="../pig-latin/README.zh.html"><strong aria-hidden="true">3.51.</strong> 猪的拉丁文</a></li><li><a href="../diamond/README.zh.html"><strong aria-hidden="true">3.52.</strong> 钻石</a></li><li><a href="../spiral-matrix/README.zh.html"><strong aria-hidden="true">3.53.</strong> 螺旋矩阵</a></li><li><a href="../palindrome-products/README.zh.html"><strong aria-hidden="true">3.54.</strong> 回文产品</a></li><li><a href="../poker/README.zh.html"><strong aria-hidden="true">3.55.</strong> 扑克</a></li><li><a href="../grep/README.zh.html"><strong aria-hidden="true">3.56.</strong> grep</a></li><li><a href="../scale-generator/README.zh.html"><strong aria-hidden="true">3.57.</strong> 音阶生成器</a></li><li><a href="../decimal/README.zh.html"><strong aria-hidden="true">3.58.</strong> 十进制</a></li><li><a href="../anagram/README.zh.html"><strong aria-hidden="true">3.59.</strong> 字谜</a></li><li><a href="../protein-translation/README.zh.html"><strong aria-hidden="true">3.60.</strong> 蛋白质翻译</a></li><li><a href="../robot-name/README.zh.html"><strong aria-hidden="true">3.61.</strong> 机器人名称</a></li><li><a href="../book-store/README.zh.html"><strong aria-hidden="true">3.62.</strong> 书店</a></li></ol></li><li><a href="../high.html"><strong aria-hidden="true">4.</strong> 难</a></li><li><ol class="section"><li><a href="../ocr-numbers/README.zh.html"><strong aria-hidden="true">4.1.</strong> OCR 号码</a></li><li><a href="../minesweeper/README.zh.html"><strong aria-hidden="true">4.2.</strong> 扫雷</a></li><li><a href="../dominoes/README.zh.html"><strong aria-hidden="true">4.3.</strong> 骨牌</a></li><li><a href="../parallel-letter-frequency/README.zh.html"><strong aria-hidden="true">4.4.</strong> 并行字母频率</a></li><li><a href="../rectangles/README.zh.html"><strong aria-hidden="true">4.5.</strong> 矩形</a></li><li><a href="../forth/README.zh.html"><strong aria-hidden="true">4.6.</strong> Forth</a></li><li><a href="../circular-buffer/README.zh.html"><strong aria-hidden="true">4.7.</strong> 循环缓冲区</a></li><li><a href="../react/README.zh.html"><strong aria-hidden="true">4.8.</strong> React</a></li></ol></li><li><a href="../untag.html"><strong aria-hidden="true">5.</strong> 未标签</a></li><li><ol class="section"><li><a href="../hexadecimal/README.zh.html"><strong aria-hidden="true">5.1.</strong> 十六进制</a></li><li><a href="../nucleotide-codons/README.zh.html"><strong aria-hidden="true">5.2.</strong> 核苷酸密码子</a></li><li><a href="../two-fer/README.zh.html"><strong aria-hidden="true">5.3.</strong> two-fer</a></li><li class="spacer"></li></ol></li><li><a href="../add-test-code.html">修改 mdBook 主题</a></li></ol>
    </nav>

    <div id="page-wrapper" class="page-wrapper">

        <div class="page">
            
            <div id="menu-bar" class="menu-bar">
                <div id="menu-bar-sticky-container">
                    <div class="left-buttons">
                        <button id="sidebar-toggle" class="icon-button" type="button" title="Toggle Table of Contents"
                            aria-label="Toggle Table of Contents" aria-controls="sidebar">
                            <i class="fa fa-bars"></i>
                        </button>
                        <!-- START - Rust Cookbook customization -->
                        <button id="edit-button" class="icon-button" type="button" title="Fork and edit" aria-label="Fork and edit"
                            aria-haspopup="true" aria-expanded="false" aria-controls="edit">
                            <i class="fa fa-edit">Edit</i>
                        </button>
                        <!-- END - Rust Cookbook customization -->
                        <button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme"
                            aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
                            <i class="fa fa-paint-brush"></i>
                        </button>
                        <ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
                            <li role="none"><button role="menuitem" class="theme" id="light">Light <span class="default">(default)</span></button></li>
                            <li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
                            <li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
                            <li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
                            <li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
                        </ul>
                        
                        <button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)"
                            aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
                            <i class="fa fa-search"></i>
                        </button>
                        
                    </div>

                    <h1 class="menu-title">exercisms.io 快速练习</h1>
                    
                        <div class="right-buttons">
                            <a href="../print.html" title="Print this book" aria-label="Print this book">
                                <i id="print-button" class="fa fa-print"></i>
                            </a>
                            
                        </div>
                    </div>
                </div>

            
            <div id="search-wrapper" class="hidden">
                <form id="searchbar-outer" class="searchbar-outer">
                    <input type="search" name="search" id="searchbar" name="searchbar" placeholder="Search this book ..."
                        aria-controls="searchresults-outer" aria-describedby="searchresults-header">
                </form>
                <div id="searchresults-outer" class="searchresults-outer hidden">
                    <div id="searchresults-header" class="searchresults-header"></div>
                    <ul id="searchresults">
                    </ul>
                </div>
            </div>
            

            <!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
            <script type="text/javascript">
                document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
                document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
                Array.from(document.querySelectorAll('#sidebar a')).forEach(function (link) {
                    link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
                });
            </script>

            <!-- // START - Rust Cookbook customization -->
            <script>
                document.getElementById("edit-button").addEventListener("click", function () {
                    var editWindow = window.open("https://github.com/chinanf-boy/exercism-rust-zh/edit/master/src/simple-linked-list/README.zh.md");
                });</script>
            <!-- // END - Rust Cookbook customization -->

            <div id="content" class="content">
                <main>
                    <a class="header" href="#simple-linked-list" id="simple-linked-list"><h1>Simple Linked List</h1></a>
<a class="header" href="#1-readme" id="1-readme"><h2>1. Readme</h2></a>
<a class="header" href="#简单链表" id="简单链表"><h1>简单链表</h1></a>
<p>编写一个使用元素(<code>Elements</code>)和列表(<code>List</code>)的简单链表实现.</p>
<p>链表是计算机科学中的一种基本数据结构，常用于其他数据结构的实现。它们在函数式编程语言(如 Clojure、Erlang 或 Haskell)中很普遍，但是在命令式语言(如 Ruby 或 Python)中很少见。</p>
<p>最简单的链表是单链表。列表中的每个元素，包含数据和一个”next”字段，指向元素列表中的下一个元素。</p>
<p>链接列表的这种变体通常用于表示序列，或推/取堆栈(也称为 LIFO 堆栈;后进先出)。</p>
<p>作为第一步,让我们创建一个包含范围(1..10)的单一链接列表,并提供反转链接列表，和转换为数组，或从数组转换的函数.</p>
<p>在使用内置链表的语言实现这一点时,实现自己的抽象数据类型.</p>
<a class="header" href="#实现提示" id="实现提示"><h2>实现提示</h2></a>
<p>不要实现结构<code>SimpleLinkedList</code>作为一个<code>Vec</code>包装。 你应该,在堆上分配节点。
这可以实现为:</p>
<pre><pre class="playpen"><code class="language-rust no_run">
# #![allow(unused_variables)]
#fn main() {
pub struct SimpleLinkedList&lt;T&gt; {
    head: Option&lt;Box&lt;Node&lt;T&gt;&gt;&gt;,
}
#}</code></pre></pre>
<p>这个<code>head</code>字段指向该链表的第一个元素(节点)。
这个实现也需要一个<code>Node</code>结构，其具有以下字段:</p>
<pre><pre class="playpen"><code class="language-rust no_run">
# #![allow(unused_variables)]
#fn main() {
struct Node&lt;T&gt; {
    data: T,
    next: Option&lt;Box&lt;Node&lt;T&gt;&gt;&gt;,
}
#}</code></pre></pre>
<p><code>data</code>包含存储的数据,以及<code>next</code>指向下节点(如果可用)或无.</p>
<a class="header" href="#为什么使用optionboxnodet而不仅用optionnodet" id="为什么使用optionboxnodet而不仅用optionnodet"><h3>为什么使用<code>Option&lt;Box&lt;Node&lt;T&gt;&gt;&gt;</code>?而不仅用<code>Option&lt;Node&lt;T&gt;&gt;</code>?</h3></a>
<p>自己试试.您将得到以下错误.</p>
<pre><code>| struct Node&lt;T&gt;
| ^^^^^^^^^^^^^^ recursive type has infinite size
...
| next: Option&lt;Node&lt;T&gt;&gt;,
| --------------------- recursive without indirection
</code></pre>
<p>这个错误在于,编译时,rust 必须知道下一个节点的大小。因<code>next</code>会是递归的(”一个节点，有一个节点-有一个节点…”)，编译器不知道要分配多少内存。相反,<a href="https://doc.rust-lang.org/std/boxed/">Box</a>是一个具有定义大小的堆指针.</p>
<a class="header" href="#资源" id="资源"><h2>资源</h2></a>
<p>受”Ruby”中面向对象设计模式的数据结构和算法的启发,即单链表.<a href="http://www.brpreiss.com/books/opus8/html/page96.html#SECTION004300000000000000000">http://www.brpreiss.com/books/opus8/html/page96.html#SECTION004300000000000000000</a></p>
<a class="header" href="#2-开始你的表演" id="2-开始你的表演"><h2>2. 开始你的表演</h2></a>
<pre><pre class="playpen"><code class="language-rust editable">pub struct SimpleLinkedList&lt;T&gt; {
   // Delete this field
   // dummy is needed to avoid unused parameter error during compilation
   dummy: ::std::marker::PhantomData&lt;T&gt;,
}

impl&lt;T&gt; SimpleLinkedList&lt;T&gt; {
   pub fn new() -&gt; Self {
       unimplemented!()
   }

   pub fn len(&amp;self) -&gt; usize {
       unimplemented!()
   }

   pub fn push(&amp;mut self, _element: T) {
       unimplemented!()
   }

   pub fn pop(&amp;mut self) -&gt; Option&lt;T&gt; {
       unimplemented!()
   }

   pub fn peek(&amp;self) -&gt; Option&lt;&amp;T&gt; {
       unimplemented!()
   }
}

impl&lt;T: Clone&gt; SimpleLinkedList&lt;T&gt; {
   pub fn rev(&amp;self) -&gt; SimpleLinkedList&lt;T&gt; {
       unimplemented!()
   }
}

impl&lt;'a, T: Clone&gt; From&lt;&amp;'a [T]&gt; for SimpleLinkedList&lt;T&gt; {
   fn from(_item: &amp;[T]) -&gt; Self {
       unimplemented!()
   }
}

impl&lt;T&gt; Into&lt;Vec&lt;T&gt;&gt; for SimpleLinkedList&lt;T&gt; {
   fn into(self) -&gt; Vec&lt;T&gt; {
       unimplemented!()
   }
}

</code></pre></pre>
<a class="header" href="#3-测试代码查看" id="3-测试代码查看"><h2>3. 测试代码查看</h2></a>
<pre><pre class="playpen"><code class="language-rust">
# #![allow(unused_variables)]
#fn main() {
#[test]
fn test_new_list_is_empty() {
   let list: SimpleLinkedList&lt;u32&gt; = SimpleLinkedList::new();
   assert_eq!(list.len(), 0, &quot;list's length must be 0&quot;);
}

#[test]
//#[ignore]
fn test_push_increments_length() {
   let mut list: SimpleLinkedList&lt;u32&gt; = SimpleLinkedList::new();
   list.push(1);
   assert_eq!(list.len(), 1, &quot;list's length must be 1&quot;);
   list.push(2);
   assert_eq!(list.len(), 2, &quot;list's length must be 2&quot;);
}

#[test]
//#[ignore]
fn test_pop_decrements_length() {
   let mut list: SimpleLinkedList&lt;u32&gt; = SimpleLinkedList::new();
   list.push(1);
   list.push(2);
   list.pop();
   assert_eq!(list.len(), 1, &quot;list's length must be 1&quot;);
   list.pop();
   assert_eq!(list.len(), 0, &quot;list's length must be 0&quot;);
}

#[test]
//#[ignore]
fn test_pop_returns_last_added_element() {
   let mut list: SimpleLinkedList&lt;u32&gt; = SimpleLinkedList::new();
   list.push(1);
   list.push(2);
   assert_eq!(list.pop(), Some(2), &quot;Element must be 2&quot;);
   assert_eq!(list.pop(), Some(1), &quot;Element must be 1&quot;);
   assert_eq!(list.pop(), None, &quot;No element should be contained in list&quot;);
}

#[test]
//#[ignore]
fn test_peek_returns_head_element() {
   let mut list: SimpleLinkedList&lt;u32&gt; = SimpleLinkedList::new();
   assert_eq!(list.peek(), None, &quot;No element should be contained in list&quot;);
   list.push(2);
   assert_eq!(list.peek(), Some(&amp;2), &quot;Element must be 2&quot;);
   assert_eq!(list.peek(), Some(&amp;2), &quot;Element must be still 2&quot;);
}

#[test]
//#[ignore]
fn test_from_slice() {
   let array = [&quot;1&quot;, &quot;2&quot;, &quot;3&quot;, &quot;4&quot;];
   let mut list = SimpleLinkedList::from(array.as_ref());
   assert_eq!(list.pop(), Some(&quot;4&quot;));
   assert_eq!(list.pop(), Some(&quot;3&quot;));
   assert_eq!(list.pop(), Some(&quot;2&quot;));
   assert_eq!(list.pop(), Some(&quot;1&quot;));
}

#[test]
//#[ignore]
fn test_reverse() {
   let mut list: SimpleLinkedList&lt;u32&gt; = SimpleLinkedList::new();
   list.push(1);
   list.push(2);
   list.push(3);
   let mut rev_list = list.rev();
   assert_eq!(rev_list.pop(), Some(1));
   assert_eq!(rev_list.pop(), Some(2));
   assert_eq!(rev_list.pop(), Some(3));
   assert_eq!(rev_list.pop(), None);
}

#[test]
//#[ignore]
fn test_into_vector() {
   let mut v = Vec::new();
   let mut s = SimpleLinkedList::new();
   for i in 1..4 {
       v.push(i);
       s.push(i);
   }
   let s_as_vec: Vec&lt;i32&gt; = s.into();
   assert_eq!(v, s_as_vec);
}

#}</code></pre></pre>
<a class="header" href="#4-答案" id="4-答案"><h2>4. 答案</h2></a>
<p><details></p>
<pre><pre class="playpen"><code class="language-rust">
# #![allow(unused_variables)]
#fn main() {
pub struct SimpleLinkedList&lt;T&gt; {
   head: Option&lt;Box&lt;Node&lt;T&gt;&gt;&gt;,
   len: usize,
}

struct Node&lt;T&gt; {
   data: T,
   next: Option&lt;Box&lt;Node&lt;T&gt;&gt;&gt;,
}

impl&lt;T&gt; SimpleLinkedList&lt;T&gt; {
   pub fn new() -&gt; Self {
       SimpleLinkedList { head: None, len: 0 }
   }

   pub fn len(&amp;self) -&gt; usize {
       self.len
   }

   pub fn push(&amp;mut self, element: T) {
       let node = Box::new(Node::new(element, self.head.take()));
       self.head = Some(node);
       self.len += 1;
   }

   pub fn pop(&amp;mut self) -&gt; Option&lt;T&gt; {
       match self.len {
           0 =&gt; None,
           _ =&gt; {
               self.len -= 1;
               self.head.take().map(|node| {
                   let node = *node;
                   self.head = node.next;
                   node.data
               })
           }
       }
   }

   pub fn peek(&amp;self) -&gt; Option&lt;&amp;T&gt; {
       self.head.as_ref().map(|node| &amp;node.data)
   }
}

impl&lt;T: Clone&gt; SimpleLinkedList&lt;T&gt; {
   pub fn rev(&amp;self) -&gt; SimpleLinkedList&lt;T&gt; {
       let mut rev_list = SimpleLinkedList::new();
       let mut next = self.head.as_ref().map(|node| &amp;**node);
       while let Some(node) = next {
           rev_list.push(node.data.clone());
           next = node.next.as_ref().map(|node| &amp;**node);
       }
       rev_list
   }
}

impl&lt;'a, T: Clone&gt; From&lt;&amp;'a [T]&gt; for SimpleLinkedList&lt;T&gt; {
   fn from(item: &amp;[T]) -&gt; Self {
       let mut list = SimpleLinkedList::new();
       for i in item {
           list.push(i.clone());
       }
       list
   }
}

impl&lt;T&gt; Into&lt;Vec&lt;T&gt;&gt; for SimpleLinkedList&lt;T&gt; {
   fn into(mut self) -&gt; Vec&lt;T&gt; {
       let mut vec = Vec::new();
       while let Some(data) = self.pop() {
           vec.push(data);
       }
       vec.reverse();
       vec
   }
}

impl&lt;T&gt; Node&lt;T&gt; {
   pub fn new(element: T, next: Option&lt;Box&lt;Node&lt;T&gt;&gt;&gt;) -&gt; Self {
       Node {
           data: element,
           next,
       }
   }
}

#}</code></pre></pre>
<p></details></p>
<hr />
<hr />
<a class="header" href="#填充相关" id="填充相关"><h2>填充/相关</h2></a>

                </main>

                <nav class="nav-wrapper" aria-label="Page navigation">
                    <!-- Mobile navigation buttons -->
                    
                    <a rel="prev" href="../hamming/README.zh.html" class="mobile-nav-chapters previous" title="Previous chapter"
                        aria-label="Previous chapter" aria-keyshortcuts="Left">
                        <i class="fa fa-angle-left"></i>
                    </a>
                    

                    
                    <a rel="next" href="../pascals-triangle/README.zh.html" class="mobile-nav-chapters next" title="Next chapter"
                        aria-label="Next chapter" aria-keyshortcuts="Right">
                        <i class="fa fa-angle-right"></i>
                    </a>
                    

                    <div style="clear: both"></div>
                </nav>
            </div>
        </div>

        <nav class="nav-wide-wrapper" aria-label="Page navigation">
            
            <a href="../hamming/README.zh.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter"
                aria-keyshortcuts="Left">
                <i class="fa fa-angle-left"></i>
            </a>
            

            
            <a href="../pascals-triangle/README.zh.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter"
                aria-keyshortcuts="Right">
                <i class="fa fa-angle-right"></i>
            </a>
            
        </nav>

    </div>

    

    
    <!-- Google Analytics Tag -->
    <script async src="https://www.googletagmanager.com/gtag/js?id=UA-128555056-1"></script>
    
    <script type="text/javascript">
        var localAddrs = ["localhost", "127.0.0.1", ""];
        if (localAddrs.indexOf(document.location.hostname) === -1) {
            window.dataLayer = window.dataLayer || [];
            function gtag() { dataLayer.push(arguments); }
            gtag('js', new Date());

            gtag('config', 'UA-128555056-1');
        }
    </script>
    

    
    <script src="../ace.js" type="text/javascript" charset="utf-8"></script>
    <script src="../editor.js" type="text/javascript" charset="utf-8"></script>
    <script src="../mode-rust.js" type="text/javascript" charset="utf-8"></script>
    <script src="../theme-dawn.js" type="text/javascript" charset="utf-8"></script>
    <script src="../theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
    

    
    <script src="../elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
    <script src="../mark.min.js" type="text/javascript" charset="utf-8"></script>
    <script src="../searcher.js" type="text/javascript" charset="utf-8"></script>
    

    <script src="../clipboard.min.js" type="text/javascript" charset="utf-8"></script>
    <script src="../highlight.js" type="text/javascript" charset="utf-8"></script>
    <script src="../book.js" type="text/javascript" charset="utf-8"></script>

    <!-- Custom JS scripts -->
    

    

</body>

</html>